Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS4410674 A
Publication typeGrant
Application numberUS 06/322,266
Publication dateOct 18, 1983
Filing dateNov 17, 1981
Priority dateNov 17, 1981
Fee statusLapsed
Publication number06322266, 322266, US 4410674 A, US 4410674A, US-A-4410674, US4410674 A, US4410674A
InventorsEdward J. Ivani
Original AssigneeIvani Edward J
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Silicone-vinyl acetate composition for contact lenses
US 4410674 A
Abstract
Contact lenses having increase oxygen permeability are fabricated at least in part from a copolymer of a vinyl siloxane and vinyl acetate.
Images(4)
Previous page
Next page
Claims(8)
I claim:
1. A composition specially adapted for the manufacturing of contact lenses having increased oxygen permeability, consisting essentially of a copolymer of comonomers consisting of about 10-90 parts by weight of a vinyl siloxane monomer copolymerized with 90-10 parts by weight of a vinyl acetate, the vinyl siloxane monomer being a polysiloxanylalkyl ester having as its structure: ##STR3## wherein P and Q are selected from the group consisting of (C1 -C7)alkyl, phenyl, and Z groups; Z is ##STR4## wherein A is selected from the group consisting of (C1 -C7) alkyl and phenyl groups; R is selected from the group consisting of methyl, ethyl, and butyl groups and hydrogen; m and n are integers of at least 1 and less than 8.
2. The composition of claim 1 wherein said copolymer is a copolymer of vinyl acetate and methacryloxypropyltri(trimethylsiloxy) silane.
3. The composition of claim 1 wherein said copolymer is a copolymer of methacryloxypropylpentamethyldisiloxane and vinyl acetate.
4. The composition of claim 1 wherein said copolymer is a copolymer of methacryloxypropyltris(pentamethyldisiloxyaryl) silane and vinyl acetate.
5. The composition of claim 1 wherein said copolymer is a copolymer of methyldi(trimethylsiloxy)silylpropylglycerol methacrylate and vinyl acetate.
6. The composition of claim 1 wherein said copolymer is a copolymer of bis(methacryloxybutyl)tetra methyldisiloxane and vinyl acetate.
7. A composition specially adapted for contact lenses having increased oxygen permeability, consisting essentially of a solid copolymer of the vinyl siloxane monomer of claim 1, vinyl acetate, and about 20-70 parts by weight of an ester of a C1 -C20 monohydric alkanol and an acid selected from the group consisting of acrylic and methacrylic acids.
8. As a new article of manufacture, a contact lens having an increased oxygen permeability, consisting essentially of the compositions of claim 1 or 2.
Description

This invention relates to a novel water-insoluble gas-permeable material, capable of giving shaped articles excellent shapeability, surface wetting property and transparency, said articles being contact lenses.

In another aspect, the invention relates to methods of increasing the oxygen permeability of polymerized acetates.

In still other respects, the invention relates to oxygen-permeable, and to wettable contact lens materials. The copolymers can be cast, molded or machined to provide contact lenses.

The prior art teaches the use of many different polymers for contact lenses. However, although these polymers possess the optical clarity necessary for corrective lenses, they suffer from other characteristics which reduce their potential utility.

Polymethylmethacrylate is rigid and durable but relatively impermeable to oxygen. The hydrogel materials based on hydrophilic polymers such as polyhydroxyethylmethacrylate are soft and have poor durability. In addition, they provide an environment which favors bacterial growth and are relatively impermeable to oxygen.

Silicone rubber is soft and resilient and is highly permeable to oxygen. However, due to the low strength of polysiloxanes, a filler which increases the refractive index of the mixture, must be added to improve the durability. Further, the precision machining and polishing which is necessary in the fabrication of a corrective contact lens is extremely difficult with the elastomeric silicone rubbers. Copolymers of silicones and methyl methacrylate have been performed and although the material is permeable, the permeability is relatively low, of the order of 350 to 650 cc-mil/100 in2 /24 hrs/atm.

Accordingly, it would be highly desirable to provide a polymeric material suitable for use in fabricating contact lenses having increased oxygen permeability, improved mechanical strength, and which is sufficiently rigid to permit precision machining and polishing. I have now discovered novel copolymers, and multi-polymers, materials which possess these properties.

The novel copolymers which I have discovered are prepared by copolymerizing a siloxane and an acetate. In particular a siloxane containing a double bond, and vinyl acetate. The double bond being preferable, but not nesessarily on one of the ends of the silicone chain.

The polysiloxanylalkyl ester monomers have a structural formula of the type ##STR1## wherein P and Q are from the class consisting of C1 -C7 alkyl groups, phenyl groups and Z groups; Z is a group consisting of ##STR2## A is selected from the class consisting of C1 -C7 alkyl groups and phenyl groups; R is selected form class consisting of methyl, ethyl, or butyl groups and hydrogen; m and n are integers less than 8.

The novel multi-polymers of the present invention comprise about 10-90 parts by weight of one or more of the siloxane monomers copolymerized with about 10-90 parts by weight of one or more acetate monomers, and in particular vinyl acetate.

The copolymers of the invention are prepared by contacting the mixture of comonomers with a free radical generating polymerization initiator of the type commonly used in polymerizing ethylenically unsaturated compounds. Representative free radical polymerization initiators include;

benzoyl peroxide

acetyl peroxide

lauroyl peroxide

decanoyl peroxide

tertiarybutyl peroxypivalate

azobisisobutyronitrile

Conventional polymerization techniques can be employed to produce the novel copolymers and multipolymers. The comonomer mixture containing between about 0.05-2.5% by weight of the free radical initiator is heated to a temperature between 30 C. and 100 C., preferably below 70 C. to initiate and complete the polymerization. The polymerization can be carried out directly in a contact lens mold to form a lens; or the polymerization mixture can be heated in a suitable mold or container to form discs, rods or sheets which can then be machined to the desired shape using conventional equipment and procedures employed for fabricating lenses from polymethyl methacrylate materials. The temperature is preferably maintained below 55 C. in order to minimize the formation of bubbles in the copolymer. The copolymers thus produced may be extruded, pressed or molded into rods, sheets or other convenient shapes which are then machined to produce the contact lenses.

The novel copolymers have vastly increased oxygen permeability in comparison to conventional contact lens materials. For example, the oxygen permeability of polymethyl methacrylate is 34 cc-mil/100 in2 /24 hr/atm, and 13 for polyhydroxyethylmethacrylate.

While some of the copolymers are inherently wettable by human tears, it may be necessary to improve the wettability of others. This can be accomplished by several methods. For example, wettability can be imparted to the copolymer by the addition of from about 0.1% to about 10% by weight of one or more hydrophilic monomers to the copolymerization mixture. Such monomers include hydroxalkyl acrylates and methacrylates wherein the alkyl group contains 1 to 4 carbon atoms, acrylic and methacrylic acid, acrylamide, methacrylamide, N-methylolacrylamide, glycidyl acrylate and methacrylate, acrylonitrile, and N-vinyl-pyrrolidone.

The rigidity of the contact lenses prepared from materials useful in the practice of this invention may be varied by changing the ratio of comonomers and/or their chemical composition. Thus contact lenses prepared from vinyl acetate monomers are more flexible than those prepared from the combination of vinyl acetate methacrylate monomers as the copolymers with the siloxanes.

The rigidity of a contact lens prepared from the materials useful in the practice of this invention may be increased, if desired, by the incorporation into the copolymer composition of 0.01% to about 2% by weight of a crosslinking monomer such as a polyol dimethacrylate or diacrylate or a polyol acrylic ester of higher functionality, for example, ethylene glycol dimethacrylate, butylene glycol dimethacrylate, and neopentyl glycol diacrylate.

The particular silicone monomers used in this invention are: methacryloxypropyltri(trimethylsiloxy)silane; methacryl oxypropylpentamethyldisiloxane; methacryloxypropltris(pent amethyldisiloxaryl)silane; methyldi(trimethylsiloxy)silyl propylglycerol methacrylate; and bis(methacryloxybutyl)tetra methyldisiloxane.

EXAMPLE 1

This example illustrates the preparation of a representative oxygen-permeable copolymer.

A mixture of 35 parts of methacryloxyproyltristrimethyl siloxysilane monomer, 65 parts of vinyl acetate and 0.04 parts of benzoyl peroxide by weight are mixed and placed in a 16150 mm test tube. The test tube is sealed and placed in an oven and maintained at 45 C. for 20 hours, or until polymerized. The copolymer is hard, colorless, transparent and rigid. The oxygen permeability is 1200 cc-mil/100 in2 /24 hrs/atm.

The oxygen permeability of a disc of polymethylmethacrylate is 34 cc-mil/100 in2 /24 hrs/atm, while that of a disc of polyhydroxyethylmethacrylate is 13 cc-mil/100 in2 /24 hrs/atm. It is interesting that the permeability of a disiloxane monomer and methyl methacrylate in the same ratio 35/65 is only 500 cc-mil/100 in2 /24 hrs/atm. The gas permeability of the CAB lens is only 900 cc-mil/100 in2 /24 hrs/atm. The present copolymer is 2.4 times more oxygen permeable than the methacrylate silicone copolymer presently used in contact lenses.

EXAMPLE 2

A mixture of 35 parts by weight of the siloxane of Example 1 is mixed with 22 parts of vinyl acetate, and 43 parts of methyl methacrylate, 0.08 parts benzoyl peroxide. The mixture is agitated in a blender for about one minute, poured into a test tube, covered and placed in an oven at a temperature of 45-50 C. for about 20 hours, or until polymerized. The material was manufactured into a contact lens and the gas permeability measured to be 1050 cc-mil/100 in2 /24 hrs/atm.

This copolymer is 110% more permeable than the siloxane methylmethacrylate polymer presently on the market. The vinyl acetate enhances and improves the permeability and wetting properties of the material.

Representative alkanol ester comonomers which may be employed in the practice of the invention include:

methyl acrylate and methacrylate

ethyl acrylate and methacrylate

propyl acrylate and methacrylate

isopropyl acrylate and methacrylate

butyl acrylate and methacrylate

amyl acrylate and methacrylate

hexyl acrylate and methacrylate

heptyl acrylate and methacrylate

octyl acrylate and methacrylate

2-ethylhexyl acrylate and methacrylate

nonyl acrylate and methacrylate

decyl acrylate and methacrylate

undecyl acrylate and methacrylate

lauryl, cetyl, and octadecyl acrylate and methacrylate.

The above monomers can be included in the copolymers to form the new composition of matter specially adapted for contact lenses having increased oxygen permeability, the composition should be about 20-70 parts by weight of an ester of a C1 -C20 monohydric alkanol and an acid selected from the class consisting of acrylic and methacrylic acids.

The above polymers are manufactured into contact lenses by trimming the 16 mm diameter rod to normally 12.5 mm. The rod is cut in 5/16 inch thick slugs, called buttons. The button is mounted into a lathe with a diamond radius cutting tool and a concave radius is cut. The button is removed from the lathe mounted and polished. The button is now remounted so a convex (power) radius can be cut, and polished onto the surface. The lens is finished in a standard manner, as those skilled in the art are familar. The material may also be molded or cast into lenses.

With some though it is evident that permutations and combinations among the various polymers and copolymers presented here can be found. It is also apparent that changes and modifications may be made without departing from the invention in its broader aspects. The aim of the appended claims, therefore is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3228741 *Jun 29, 1962Jan 11, 1966Mueller Welt Contact Lenses InCorneal contact lens fabricated from transparent silicone rubber
US3808178 *Jun 16, 1972Apr 30, 1974Polycon LaboratoriesOxygen-permeable contact lens composition,methods and article of manufacture
US4097436 *Jun 11, 1976Jun 27, 1978Dynamit Nobel AktiengesellschaftHydrolyzed vinyl acetate-vinyl alkoxy silane polymers
US4120570 *Sep 6, 1977Oct 17, 1978Syntex (U.S.A.) Inc.Polysiloxanylalkyl acrylate or methacrylate and an alkyl acrylate or methacrylate
US4139513 *Mar 20, 1978Feb 13, 1979Toyo Contact Lens Co., Ltd.Bulk addition polymerized trisiloxane-methacrylate
US4139692 *Mar 20, 1978Feb 13, 1979Toyo Contact Lens Co., Ltd.Copolymer for contact lens, its preparation and contact lens made thereof
US4216303 *Jan 26, 1979Aug 5, 1980George F. TsuetakiOxygen-permeable contact lens compositions, methods and articles of manufacture
US4246389 *Jun 25, 1979Jan 20, 1981American Optical CorporationAcrylic siloxanes copolymerized with hydroxy ethyl methacrylate and vinyl pyrrolidone
US4248989 *Sep 11, 1979Feb 3, 1981Novicky Nick NOxygen permeable hard and semi-hard contact lens compositions, methods and articles of manufacture II
US4330383 *Jul 28, 1980May 18, 1982Polymer Technology CorporationRemoval of monomer residue by high-energy radiation of an unsaturated monomer-siloxanyl alkyl ester vinyl copolymer
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4500695 *Jun 13, 1983Feb 19, 1985Ivani Edward JUsing a vinyl siloxane
US4508884 *May 25, 1983Apr 2, 1985Coopervision, Inc.Copolymer of unsaturated silicone ester, unsaturated ester, hydrop
US4645811 *Apr 2, 1984Feb 24, 1987Oculus Contact Lens CompanyContact lenses nonwettable by proteins comprising an acrylate-siloxane copolymer also containing an acrylic acid and n-(1,1-dimethyl-3-oxobutyl) acrylamide
US4665145 *Jul 5, 1984May 12, 1987Shin-Etsu Chemical Co., Ltd.Addition polymerization
US4861840 *Dec 3, 1986Aug 29, 1989Barnes-Hind, Inc.Novel siloxanyl acrylic monomer and gas-permeable contact lenses made therefrom
US6432137Sep 7, 2000Aug 13, 2002Medennium, Inc.High refractive index silicone for use in intraocular lenses
US6727336May 9, 2000Apr 27, 2004Menicon Co., Ltd.Siloxane macromonomer having at least two active unsaturated group copolymerized with lower fatty acid vinyl ester; lipid-stain resistance, wettability and oxygen permeability,flexibility
US6951894Aug 17, 2000Oct 4, 2005Ciba Vision CorporationExtended wear ophthalmic lens
US7468398Jun 7, 2005Dec 23, 2008Ciba Vision CorporationExtended wear ophthalmic lens
US7538146Dec 30, 2006May 26, 2009Ciba Vision CorporationExtended wear ophthalmic lens
US7553880Dec 30, 2006Jun 30, 2009Ciba Vision CorporationBalanced oxygen, ion and water permeability; cornea health, wearer comfort, on eye movement; core composed of crosslinked siloxane copolymerized with dimethylacrylamide, 2-hydroxyethyl methacrylate and/or N-vinylpyrrolidone
US8415404Jun 4, 2010Apr 9, 2013Ciba Vision CorporationExtended wear ophthalmic lens
US8568626Oct 16, 2008Oct 29, 2013Ciba Vision CorporationExtended wear ophthalmic lens
EP1176454A1 *May 9, 2000Jan 30, 2002Menicon Co., Ltd.Ocular lens materials and process for producing the same
EP1266914A1 *May 22, 2002Dec 18, 2002Kusumoto Chemicals, Ltd.Flow-and-leveling agents for waterborne coatings
Classifications
U.S. Classification526/279, 351/159.33
International ClassificationG02B1/04, C08F218/08, C08F230/08
Cooperative ClassificationG02B1/04, C08F230/08, C08F218/08
European ClassificationG02B1/04, C08F230/08, C08F218/08
Legal Events
DateCodeEventDescription
Dec 31, 1991FPExpired due to failure to pay maintenance fee
Effective date: 19911020
Oct 20, 1991LAPSLapse for failure to pay maintenance fees
May 28, 1991REMIMaintenance fee reminder mailed
Feb 4, 1987FPAYFee payment
Year of fee payment: 4